TP 13312

•	Foreword
•	Section 1
•	Section 2
•	Neurology
•	Cardiovascular
•	Diabetes
•	Asthma
•	Other Policies
•	Contacts
•	Alternate Formats

Chapter 3: Dysrhythmias

• Supraventricular Dysrhythmias
• Sinus Node Dysfunction
• Atrial Fibrillation
• Pre-Excitation Syndromes
• Ventrical Dysrhythmias
• Conduction disorders
• Bundle Branch Block
• Cardiac Pacemakers
• Implanted Cardiac Defibrillators 

All applicants with dysrhythmias should be evaluated with two questions in mind: what is the nature of the disability produced by a given arrhythmia i.e., how incapacitated is the applicant when the dysrhythmia occurs and what is the underlying condition of the heart i.e., is structural heart disease present. Both questions must be answered before a decision can be made about an applicant’s fitness to fly.

Supraventricular Dysrhythmias

Supraventricular tachydysrhythmias may accompany self-limited illnesses e.g., pneumonia or treatable conditions e.g. hyperthyroidism. In such cases, the need to restrict flying will be only temporary. 

Applicants in whom treatment with an antiarrhythmic agent is successful need not be restricted from flying. Successful use of ablation therapy should be confirmed with repeat electrophysiologic study 3 months later in those individuals whose arrhythmia was previously incapacitating. Applicants who undergo AV nodal ablation of the slow pathway are more likely to be reconsidered favourably because of the lower risk of development of heart block. 

Sinus Node Dysfunction

Isolated sinus node dysfunction including sinus bradycardia may occur in healthy people, particularly those involved in vigorous exercise programs. Such a finding (a consequence of high vagal tone) need not necessarily be considered an abnormality. Provided the dysfunction does not interfere with mental function, the licence holder need not be restricted from flying. Where there is concern e.g. extreme bradycardia, a thorough symptom history should be followed by Holter monitoring and a treadmill exercise test. Even in a healthy applicant, no R-R interval should exceed 4 sec during sleep or 3 sec while awake.

Atrial Fibrillation

There are 3 major concerns in the assessment of the risk of incapacitation in an individual with atrial fibrillation. The first is the hemodynamic effect of the arrhythmia itself. The second is the risk of embolism and the third is the risk of bleeding as a consequence of anticoagulation. Since risk is additive, the aggregate risk must remain within acceptable limits. Therefore it is possible that flying may be allowed for selected aircrew depending on their condition and the effect of treatment. The lowest risk is seen in those below 65 years of age who have intermittent or chronic, lone atrial fibrillation, i.e. no identifiable cause of the arrhythmia and no underlying structural heart disease. Annual follow-up in such cases should include 24 hr Holter monitoring. Individuals with atrial fibrillation who have 2 or more of the 5 major risk factors, including age > 65 years, structural heart disease, diabetes, high blood pressure and previous thromboembolism are considered to be above the threshold level of risk even when fully anticoagulated. Thus, older licence holders with structural heart disease generally have a cumulative risk of embolism and bleeding secondary to anticoagulation that exceeds the limit for medical certification. 

Pre-Exitation Syndromes

Not all cases of Wolff-Parkinson-White (the most common type of pre-excitation) are associated with incapacitating dysrhythmias. The risk of incapacitating symptoms in people who have never had tachycardia is low but is not known with any precision. Applicants with only an electrocardiographic indication, whether chronic or intermittent, and no history of palpitations may be fit to fly if their response to a treadmill exercise test is normal in all respects particularly if evidence of preexcitation is lost at accelerated heart rates. Such individuals are unlikely to conduct at a dangerously
high rate if in atrial fibrillation. Electrophysiologic studies are not required in such cases. 

Medical certification in a restricted capacity may be considered 3 months after a symptomatic episode of tachycardia has been controlled with medication. Applicants in whom accessory pathway connections have been ablated surgically or by catheter techniques are considered fit if at 3 months they are asymptomatic and their electrocardiogram shows no evidence of pre-excitation. In some cases repeat electrophysiologic studies may be required 3 months after surgery to confirm a successful intervention. 

Ventricular Dysrhythmias

The main concern with ventricular dysrhythmias is the underlying condition of the myocardium. A careful assessment should be done to determine the presence of structural heart disease. If the myocardium is normal, ventricular ectopy should be judged on the basis of the disability produced and, to a lesser extent, on the presence or absence of complex forms. Although the complexity of premature ventricular beats is poorly correlated with risk in the presence of normal myocardial tissue, the appearance of multiform or repetitive forms of ventricular ectopy i.e., couplets, runs, should indicate the need for a thorough cardiac examination since these and other high grade forms of ectopy are more commonly seen in association with structural heart disease. If the ventricular ectopic beats have a LBBB pattern particularly with a vertical axis, right ventricular dysplasia should be ruled out by either invasive (ventriculography) or non-invasive (echo, MRI or radionuclide scintigraphy) tests. 

The presence of more than 1 PVC on a resting 12- lead electrocardiogram warrants 24 hour Holter monitoring.

Exercise-induced ventricular tachycardia can occur in healthy people. These events are usually selfterminating. Medical certification need not be restricted in such cases unless there are recurrent episodes. Individuals with sustained tachycardias are unfit.

Conduction Disorders

First-and-second-degree (type 1) atrioventricular conduction delay can be seen during rest (particularly sleep) in healthy people with a structurally normal heart who engage in vigorous exercise. High grade atrioventricular block should be investigated to rule out heart disease and to determine the risk of progression to complete heart block. Likewise first and second-degree block with structural heart disease should be investigated to determine the risk of
progression to complete heart block. 

Bundle Branch Block

Left bundle branch block and right bundle branch block of recent onset, indicate the need for a cardiovascular examination to rule out heart disease, especially ischemic heart disease. Isolated right bundle branch block and left hemiblocks that are longstanding are generally benign. 

Cardiac Pacemakers

The reliability and safety of implantable cardiac pacemakers is well established and continues to improve. Conditions in which there is little or no structural heart disease and for which the requirements for a pacemaker are intermittent need
not disqualify a licence holder from flying. Each case will need to be considered individually and not before 3 months after successful implantation. 

Follow up requires a pacemaker clinic report including an indication of the underlying rhythm and escape rate.

Implanted Cardiac Defibrillators

It is highly improbable that an individual with an implanted cardiac defibrillator can be considered fit. However individual cases can be considered provided there is no structural heart disease and even in such cases only a restricted medical certification may be granted. Such restricted certification will not be considered before completion of a trial period of at least 3 years. During this time defibrillator function and cardiac response must be carefully monitored to ensure that any dysrhythmias are properly identified, promptly corrected and that any episodes are not incapacitating.